This is a fascinating article published by Friends of the Earth which gives all gardeners food for thought!…
They will prefer full sun but do not bloom well if allowed to dry out. You will need to divide these plants every 2 to 3 years to keep them growing vigorously.
Divide every 2 to 3 years to keep vigorous.
Pests, diseases or disorders
Powdery mildew may be problem.